diff --git a/configure.ac b/configure.ac
index 9de62ae66..f16facdfa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -199,6 +199,9 @@ then
 
     # Enable multiple attribute additions such as DC
     AM_CFLAGS="-DWOLFSSL_MULTI_ATTRIB $AM_CFLAGS"
+
+    # Enable checks on ECC keys that are imported
+    AM_CFLAGS="-DWOLFSSL_VALIDATE_ECC_IMPORT $AM_CFLAGS"
 fi
 
 
@@ -1626,6 +1629,9 @@ then
         AC_MSG_ERROR([cannot enable fpecc without enabling ecc.])
     fi
     AM_CFLAGS="$AM_CFLAGS -DFP_ECC"
+
+    # Enable checks on ECC keys that are imported
+    AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_VALIDATE_ECC_IMPORT"
 fi
 
 
diff --git a/wolfcrypt/src/integer.c b/wolfcrypt/src/integer.c
index 668253303..4c81c653f 100644
--- a/wolfcrypt/src/integer.c
+++ b/wolfcrypt/src/integer.c
@@ -965,7 +965,7 @@ int mp_invmod (mp_int * a, mp_int * b, mp_int * c)
 #endif
 {
   /* b cannot be negative */
-  if (b->sign == MP_NEG || mp_iszero(b) == MP_YES) {
+  if (b->sign == MP_NEG || mp_iszero(b) == MP_YES || mp_iszero(a) == MP_YES) {
     return MP_VAL;
   }